Lens-grinder



D. TILLYER AND L. W. BUGBEE.

LENS GRINDER.

APPLICATION FILED NOV. 30, 1917.

ggy 'yfig Patented July 27, 1920.

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INVENTOR L. .wBuqsca Q 5.13 TILLYEE.

I r ,4 TTORNEYS E. D TILLYER AND L. W. BUGBEE.

LENS GRINDER.

APPLICATION FILED NOV. 30. 1917.

Patented July-27, 1920.

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2 SHEETS nw IVTOI? L w BUGBEE E .D 'r LLYER er 2a ATTORNEYS UNITEDSTATES,

PATENT OFFICE.

EDGAR D. TILLYER AND LUCIAN W. BUGBEE, SOUTHTBRIDGE, MASSACHUSETTS,

ASSIGNORS T0 AMERICAN OPTICAL COMPANY, OF SOUTHBIR-IDGE, MASSACHU-SETTS, A VGLUNTARY ASSOCIATION OF MASSACHUSETTS. I

LENS-GRINDER.

Specification of Letters Patent.

Application filed November 80, 1917. Serial No. 204,666.

To all whom it may concern:

Be it known that we, EDGAR D. TILLYER and LUCIAN W. BUGBEE, citizens ofthe United States,residing at Southbridge, in the county of Worcesterand State of Massachusetts, having invented certain new and usefulImprovements in Lens-Grinders, of which the following is aspecification. This invention relates to improvements in grindingmachinery and has particular reference to a novel and improvedconstruction of machine for use in the grinding or constructing ofophthalmic lenses.

One of the leading objects of the present invention is the provision ofapparatus which may be employed to simultaneously generate, form orproduce a series of lenses, all having the same curve, and which willserve to con rol said curve and prevent wearing of the tool from thedesired curve.

A further object of the present invention is the provision of a machineparticularly adapted for use in the simultaneous formation of the twosurfaces of a one-piece bifocal lens, which machine shall be so formedand constructed that a number of lenses may be ground or polished on itat one time, and in which the curves of both the reading and distanceportion of the tools will be auto-' matically trued, or corrected duringthe grinding operation.

()ther objects and advantages of our improved construction should bereadily apparent by reference to the following specification taken inconnection with the accompanying drawings, and it will be understoodthat we may make any modifications in the specific details ofconstruction shown and described within the scope of the appended claimwithout departing from, or-exceeding the spirit of our invention.

Figure I represents a vertical sectional view of one embodiment of ourcomplete machine.

Fig. II represents a horizontal sectional view with the upper portion ofthe machine removed.

Fig. III represents a semi-diagrammatic view illustrating the driving ofthe several spindles.

Fig. IV represents a fragmentary semidiagrammatic plan View illustratinga different arrangement of our truing devices.

F 1g. V represents an enlarged sectional view through one of the lensblocks and intimately associated parts.

Fig. VI represents a modified form of truin wheel.

ig. VII represents a detail view of the resilient bearing.

Inthe drawings, the numeral 1 designates as an entirety the frame-0f ourimproved machine, formed with the bearings 2 for the main drive shaft 3,which is connected as by the belt 4 and pulleys 5 and 6 with the driveshaft 7 of the horizontally rotating table 8. This table 8 is preferablymounted on suitable ball or roller bearings 9 supported by the plate 10and has formed thereon the annular grinding tool or lap 11, preferablyformed with a central groove 12 of one curve and a pair of similarcurved portions 13 disposed on each side of the central groove 12, thetwo portions '13 together being part of a circle in transverse section,asshould be clearly understood by reference to Fig. V.

J ournaled in'the bearings 14 at the upper portion of the frame is asecond driven shaft 15 connected by the pulley 16 and belt 17 with themain drive shaft, and itself being provided with the driving gear 18meshing with the pinions 19 on the lens driving spindles ,20, which havebeen illustrated as six in number, disposed about the shaft 15 as acenter, and with their centers directly over the center of the groove 12in the annular la 11.

t willv thus be seen that driving of the shaft 7 will rotate the table 8and annular lap carried thereby, while at the same time the driving ofthe shaft 15 through the gear 18 and pinions19 will serve to rotate orspin the lens spindles 20 over the lap.

The spindles 20 are provided on their lower ends with the balls 21adapted to fit in suitable recesses in the end of the lens blocks 22,and are provided with the arms 23 adapted to loosely fit within thesockets 24 of the blocks so that the blocks are held for slight rockingmovement to accurately fit against the lap and at the same time have adriving connection with the spindles so that the Patented July 2'7,1920.

blocks and thus the lenses 25 carried thereby are spun around over thegroove of the lap. It will thus be seen that an extremely desirablegrinding movement is provided, in that the table with its annular lap isrotating in one direction and at one speed, while the lenses arespinning against the groove "in the lap at a different speed and thereis thus an absolute break-up of movement between the parts and verysatisfactory grinding 1s accomplished. To permit of ready observation ofthe grinding and removal of any particular block and lens, as desired,without disturbing the other parts, we preferably secure on each'of thespindles 20a shift collar, as 26', adapted to be engaged by the shiftlever 27 intermediately pivoted to the frame 1 in such position thatdepression of the handle portion of the shift. lever 27 will cause theoperatingportion to engage the collar and raise the spindle until thepinion 18 is out of mesh with the gear 19, slight further movement ofthe handle swinging the lever past center to lock the spindle in raisedposition until the handle is again shifted. It will thus be seen that onaccount of this lifting movement the block may be readily disenga edfrom the lower end of the spindle. If desired a suitable latch orlocking device 28 may be provided on the block to interlock with thegroove 29 on the lower end of the spindle'so that the block itself willbe raised with the spindle and may be left there without attentionindefinitely if desired, in place of it being necessary to grasp theblock to prevent it being carried around with the table, as mightotherwise be necessary.

The only difliculty to be experienced in connection with a grindingmachine of the character just described is due to the fact that in timethe transverse curve or curves of the annular lap may wear off true, sothat the lenses will not possess exactly true spherical curves ofdesired dioptric value.

It is, therefore, one of the main objects of the present invention toprovide means for automatically truing up or keeping these curves inshape, and in the accomplishment of this result we have shown at theright in Fig. I, supported in suitable bearings 30, the shaft 31 drivenas by the belt 32 from the main drive shaft 3, and bearing thereon thecentral section of a sphere 33, the curve of the face of the spherebeing the same as the transverse curve against which it fits. It will,of course, be, understoodthat when it is desired to use our machine forplain spherical grinding, the groove portion 13 will extend from oneside to the other of the lap, and that in this event the face of thetruing member 33 will fit the entire transverse curve of the groove atthe point of contact, but in the present instance we have shown ourmachine as used for bifocal grinding, in which event there is preferablya truer provided for the central groove 12 and a second truer for themain'groove 13, although if preferred a truer such as shown in Fig. VIcould be substituted for the member 33 of Fig. I, doing away with thesup" The essential advantage plemental truer. 4 of the form shown inFig. I, however, re-

sides in the fact that by using the two separate truing devices each maybe a section of a sphere of the-desired curve, and in this way the lifeand efficiency of the truing device will be much greater than would bethe life of the truing device of Fig. VI, which would wear away andrequire replacement much quicker.

. In Fig. II, we have illustrated our truing devices with their axes ofrotation extending transversely of theportion of the annular lap whichthey engage, but in Fig. IV we have shown them as extending parallelwith the portion of the lap they engage, the general operation in eithercase being the same,

but slightly better results being obtained" be supported in floatingbearings whose position is controlled as by the springs 36, to insure alight even engagement between the parts atall times.

From the foregoing description taken in 7 connection with theaccompanying drawings, the construction and advantages of our 1 lensgrinding machine should be readily apparent, and 1t will be seen that wehave provided a novel and improved machine to 'produce a number ofspherical or bifbcal lenses at a .single operation, in which any of' thespindles may be readily shifted into inoperative position as desiredwithout affecting the operation of the remaining spindles, and in whichthe curve of the tool is kept at all times constant irrespective of thetendency of the lenses to wear same 'ofi' true, and consequently that wehave provided a machine in which extremely high grade lenses may beeconomically and satisfactorily produced.

We claim:

A lens grinding machine, including 'a.

frame, a rotating table bearing an annular grinding tool, said toolhaving a main.

spherical transverse curve and a supplemental transverse portion ofdifferent curve, a main drive gear carried by the frame, a plurality ofspindles having pinions at their upper ends to mesh with the drive gear,and In testimony whereof We have affixed our a plurality of lenses attheir lower ends for signatures, in presence of two witnesses.engagement with the tool, whereby a pair of EDGAR D TILLYER surfaces ofdifferent foci will be formed on LUCIAN BUCBEE' each of the lenses, andmeans for independ- I ently shifting the spindles to move theirWitnesses:

pinions out of mesh with the main drive HARRY H. STYLL,

gear. v H. K. PARSONS.

